RSA 2048 is secure for a website. You need to use a CSR and a private key with a CA (Certificate Authority) that creates a certificate, and you then need to paste the certificate for your domain on the “Certificate” field and click on “Upload Certificate”.

Des3,aes192 etc. I have private key that is format in aes192 ,your system isnot support this key.

I’m sorry, but how do you have an AES 192 private key? Isn’t AES is an encryption cipher? SSL private keys just use RSA, without any encryption. These keys are subsequently used for encryption, but are not encrypted themselves.